Biocidal Monomeric BCM salts

ABSTRACT

Preparation of biocidal polymers and copolymers based on free radical-polymerizable and copolymerizable ethylenically unsaturated monomers containing monomer units composed of BCM salts of ethylenically unsaturated carboxylic acids, sulfonic acids or phosphonic acids, solutions thereof and preferably aqueous dispersions thereof. Processes for their preparation and their use as fungicidal and algicidal impregnating agents, paints and finishing agents for scumbles and dispersion paints providing protection against blue staining on wood, for synthetic resin renderings, for exposed concrete paints and for textile finishing agents.

This application is a division of U.S. patent application Ser. No.994,138 filed Dec. 21, 1992, now U.S. Pat. No. 5,252,321.

The invention relates to biocidal polymers and copolymers, preferablyaqueous biocidal plastic dispersions, processes for their preparation byfree radical polymerization or copolymerization from monomeric BCM saltsof ethylenically unsaturated and free radical-polymerizable orcopolymerizable acids and their use as fungicidal and algicidal paintsand finishing agents, as scumble for wood protection, for dispersionpaints with protection against blueing on wood, for synthetic resinrenderings, for paints for exposed concrete and for textile finishingagents.

Many types of wood, including numerous home-grown woods, have only a lownatural durability. Especially when exposed to the effects of moisture,for example when used outside closed rooms or within damp and poorlyventilated rooms, the risk of the colonization and destruction of woodleft in the natural state by fungi and microorganisms is high. There hastherefore been no lack of attempts to reduce the susceptibility oftimber. Thus, solutions or mixtures of polymer binders with fungicidalcompounds, frequently phenol derivatives, such as, for example, PCP,trichlorophenols, ortho-phenylphenol (for example Preventol),polyhalogenated hydrocarbons (for example the insecticide HCH or thefungicide 2,4,5,6-tetrachloro-m-phthalodinitrile (Nopcocide N40)) or tincompounds (tributyltin oxide) or their reaction products with carboxylicacids, such as, for example, oleic acid, naphthenic acid or benzoicacid, in combination with organic solvents have been and are stillfrequently being used as wood protection agents. Disadvantages of thesesystems are, inter alia, considerable toxicological reservations withregard to the active compounds, the combustibility of many of theseagents and their powerful inherent odor, which precludes or restrictsuse in, for example, living areas, and also the high price of thesolvents and the negative effects on human health and the environmentwhen they are released into the air. In addition, the efficiency of thewood protection agents disclosed hitherto often also declines rapidly,since the biocidal active compounds, despite the fact that they arefrequently insoluble in water, are relatively rapidly leached out, forexample on exposure to weather, or are displaced via the gas phase andare then able to contaminate the environment as a consequence of theirusually inadequate biodegradability.

The use of anionic plastic dispersions as binders for paints andrenderings and for scumble treatment of wood has already been disclosed.Products of this type are environmentally friendly and comply very wellwith the requirements for a wood coating, including from the aestheticstandpoint. A disadvantage is that when they are used on their own theyare not able, because of the lack of biocidal activity, to protect thewood adequately against decay and infestation by fungi. An effectiveaddition of the abovementioned free active compounds, such as phenolcompounds, polyhalogenated hydrocarbons, tin compounds, with theirassociated disadvantages which have already been mentioned is, however,possible only with difficulty. They can, for example, not be recommendedfor interior use, in particular on toxicological grounds. Moreover,despite their insolubility in water, when used outdoors they alsoprovide only short-term protection when subjected to leaching out.

There has therefore been no lack of attempts to replace the activecompounds used hitherto by new suitable active compounds less toxic tomammals. However, the active compounds disclosed hitherto usually havethe disadvantage that they act only against a specific fungus and, insome cases, have to be added to the plastic dispersions in the form oforganic solutions, with correspondingly undesirable consequences, or inthe form of solids, which demands additional measures for mixing in andin the case of polar active compounds frequently resulted in excessiveleaching out from paints prepared therefrom.

Especially when providing aqueous or water-dilutable binders, such asplastic dispersions or water-soluble resins, such as are nowadaysincreasingly used in all coating sectors, with a biocidal finish, thereare further problems. Thus, some of the new active compounds are notstable in an aqueous environment and are hydrolyzed, with loss ofactivity, when the binder is stored (example: PREVENTOL A4=N,N-dimethyl-N'-phenyl-N'-(fluorodichloromethylthio)sulfamide orPREVENTOL A5=N,N-dimethyl-N'-phenyl-N'-(fluorodichloromethylthio)-sulfamide).

Some of the other, usually organic, compounds are sparingly soluble inwater and therefore can be introduced only with difficulty or via polarauxiliary solvents or solubility promoters.

Whereas there are new environmentally friendly application methods andalso new active compounds (for example Xyligen B (triazole derivative))for the protection of wood against wood-destroying fungi (for examplefrom the group comprising the Basidiomycetes, such as, for example,Poria monticola, Gleophyllum trabeum, Lenzites trabea, Lentinuslepideus, Coniophora puteana, Trametes versicolor) by dipping insolutions containing active compound, the infestation with blue stainfungi in the outside regions of fences and wooden window frames is stilla problem which cannot be solved satisfactorily.

It is known that BCM (benzimidazolylcarbamic acid methyl ester) is acompound which has a very good fungicidal action both against blue stainfungi (for example Aureobasidium pullulans and Sclerophoma pityophila)and against molds (such as Aspergillus niger) and soft rot fungi (forexample Chaetomium globosum), i.e. that it advantageously has a verybroad spectrum of action.

A disadvantage is the exceptionally low solubility in all conventionalorganic solvents and also, in particular, in water. The reaction withreactive organic compounds to give derivatives which have bettersolubility or covalent linking to the binder via functional groupsduring the polycondensation reaction is indeed possible, but hithertothis has led to a reduction in the biocidal action extending to completeloss of protection. Hitherto the only possibility for fungicidaltreatment of a binder with BCM consisted in adding BCM as activecompound in powder form to the binder formulation and incorporatingwell. Transparent thick or thin film scumbles are, however, notobtainable by this means since the active compound in the requisiteconcentration causes the coating to appear opaque, which is undesirablein the case of exterior use on window frames and fences. Particularly inthe field of aqueous binders, such as water-soluble resins or plasticdispersions, where a very good biocidal spectrum of properties can becomplemented by up-to-date protection of the environment and theworkforce, it would be necessary to be able to employ an ideal anduniversal biocidal active compound which remains biocidally activewithout time limit in the binder formulations and the paints, coatingsand impregnations prepared therefrom.

The object on which the invention was based was, thus, to provide anenvironmentally friendly, biocidal binder, preferably in the form of anaqueous plastic dispersion, which is suitable for the preparation ofcoating compositions or primers providing wood with protection againstblueing, in which the biocidal active compound is distributed ashomogeneously as possible and has as long as possible a period ofbiocidal action coupled with a broad spectrum of action, and thebiocidal active compound has low leachability and optionally alsoprotects against infestation by algae, which can often be important, forexample for facades and for exposed concrete.

It has now been found, surprisingly, that the above-mentioneddifficulties can be overcome and the stated object can be achieved ifdispersions of polymers are used in which the macromolecules containmonomer units composed of benzimidazolylcarbamic acid methyl ester salts(BCM salts) of ethylenically unsaturated carboxylic acids orethylenically unsaturated sulfonic acids or ethylenically unsaturatedphosphonic acids, preferably of ethylenically unsaturated carboxylicacids.

The invention therefore relates to biocidal polymers or copolymers basedon free radical-polymerized or copolymerized ethylenically unsaturatedmonomers, wherein the polymers or copolymers contain monomer unitscomposed of BCM salts of the formula I ##STR1## in which A.sup.⊖ is ananionic ethylenically unsaturated carboxylic acid or sulfonic acid orphosphonic acid radical, and said monomer units are polymerized in thebiocidal macromolecules via the ethylenic double bond of the radicalA.sup.⊖, or solutions or aqueous dispersions of said polymers orcopolymers, preferably aqueous dispersions.

The content of monomer units composed of BCM salts of the formula I inthe biocidal polymers or copolymers is variable over a wide range and ispreferably 0.001 to 5% by weight, in particular 0.02 to 1% by weight,with respect to the biocidal polymer or copolymer. The biocidalmacromolecules can also contain monomer units composed of different BCMsalts of the formula I, preferably those having acid radicals of thesame type in the radical A.sup.⊖. Homopolymers or copolymers of BCMsalts of the formula I are also possible and can be advantageous in somecases.

According to the invention, the biocidal polymers or copolymerspreferably contain such monomer units composed of BCM salts of theformula I in which the anionic radical A.sup.⊖ in formula I is anacrylate, methacrylate, fumarate, maleate, crotonate, itaconate,styrenesulfonate, acrylamidomethylpropanesulfonate, acrylamidoglycolicacid methyl ether, vinylsulfonate, vinylphosphonate oracrylamidomethylphosphonate radical. Particularly preferred anionicradicals A.sup.⊖ are acrylate, methacrylate, vinylsulfonate andacrylamidomethylpropanesulfonate radicals.

The invention also relates to the biocidal monomeric BCM salts of theformula I, in which the radical A.sup.⊖ in formula I has theabovementioned meanings.

According to the invention, the biocidal monomeric BCM salts of theformula I can be obtained by reaction of stoichiometric amounts of BCMand monomeric ethylenically unsaturated acids of the formula HA, inwhich A has the same meaning as A.sup.⊖ in formula I. The reaction canbe carried out in bulk. However, it is preferably carried out in aqueoussolution, the acid of the formula HA being dissolved in water and theBCM being introduced into the aqueous solution, the reaction takingplace with a slight rise in the temperature of the solution. By coolingthe aqueous solution to close to the freezing point of water, theresulting BCM salt of the formula I crystallizes out and can be obtainedin pure form.

The BCM salts of the formula I prepared according to the invention aregenerally readily soluble, both in water and in customary freeradical-polymerizable and/or copolymerizable ethylenically unsaturatedmonomers. The BCM salts of the formula I can therefore be used directlyand without problems for emulsion and suspension polymerization orcopolymerization in an aqueous medium or also for solution or bulkpolymerization or copolymerization in organic solvents, or in the formof a solution in corresponding comonomer components. The polymerizationand copolymerization of the BCM salts of the formula I is preferably tobe carried out in the absence of excess free inorganic or freenon-copolymerizable organic acids since otherwise, in particular inaqueous media, there is a risk of anion exchange between the BCM saltsof the formula I and the free acids, which can lead to disadvantages.

Biocidal polymers or copolymers according to the invention containingcontents according to the invention of monomer units composed of BCMsalts of the formula I, their solutions or their aqueous dispersions canalso be obtained by reacting corresponding starting polymers orcopolymers which contain monomer units of the formula HA, in which A hasthe meaning as in formula I, in their acid HA form, in anhydrous polarorganic solvents with a stoichiometric amount of pulverulent BCM orsoluble BCM salt of a low-molecular weak acid, preferably a weak organicacid which can be distilled in its free form, removing the weak organicacid which may have been liberated, preferably by distillation, andisolating the biocidal polymer or copolymer according to the inventionfrom the organic solution in the conventional manner, or, after addingemulsifier, converting it into an aqueous dispersion and then optionallyremoving the polar solvent, preferably by distillation. Suitable polarorganic solvents are, for example, inert, low-molecular alcohols,esters, ethers and ketones, preferably methanol, propanol, ethylacetate, acetone, methyl ethyl ketone, dioxane and tetrahydrofuran.

A few characteristic properties of monomeric BCM salts of the formula I,such as, for example, the melting point, the solubility in water and thesolubility in butyl acrylate, are summarized in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Properties of monomeric, polymerizable BCM salts of the formula I                                Melting point °C.                                                                Solubility in H.sub.2 O                                                                Solubility in butyl                     BCM salt of the formula I                                                                        (capillary method)                                                                      at 25° C.                                                                       acrylate at 25° C.               __________________________________________________________________________     ##STR2##          195 (with decomp.)                                                                      <10%     <10%                                     ##STR3##          235 (with decomp.)                                                                       <5%     <10%                                     ##STR4##          polymerizes on recrystallization                                                        >20%     <10%                                     ##STR5##          90-91     >20%     <10%                                     ##STR6##            --      >20%     <10%                                    __________________________________________________________________________

For polymerization the BCM salts of the formula I can be used either inbulk or in the form of solutions of the BCM salt in the aqueous acid HAor in the free acid HA. When preparing finely divided aqueous pureacrylate or styrene-acrylate dispersions, in which the startingcomonomers used in many cases contain ethylenically unsaturated acidssuch as acrylic acid (AA) or methacrylic acid (MAA), the amount of BCMstoichiometrically required for salt formation is advantageouslydissolved in the requisite amount of the ethylenically unsaturated acidwith formation of the salt and the solution of the resulting monomericBCM salt in the unsaturated acid is used in place of the pureunsaturated acid. If BCM salts of the formula I are used in thepreparation of cationic (Example 5) or amphoteric dispersions (Example4), dispersions result which have very good fungicidal activity and, atthe same time, particularly high algicidal activity. The level ofactivity against one or other microorganism can also be varied withinwide limits by means of the choice of the nature and amount of thecationic surfactant to be used.

The invention therefore also relates to the use of aqueous biocidalplastic dispersions according to the invention which are based on freeradical-polymerized or copolymerized ethylenically unsaturated monomershaving biocidally active contents of monomer units of the formula I forthe impregnation and priming of absorbent substrates and for painting orcoating solid substrates, the biocidal plastic dispersions being anionicor cationic or amphoteric dispersions which contain biocidally activedispersion polymers or copolymers, in which the polymer particles haveaverage particle diameters of 0.02 to 1 μm, preferably 0.05 to 0.5 μm.

According to the invention, the dispersions are preferably used forimpregnating and priming absorbent substrates, in particular renderedsurfaces in the building sector, including sanded-down plaster, andwood, paper and cellulose-containing products, and also for painting orcoating any desired solid substrates and also as textile finishingagents.

The solids content of the biocidal dispersions to be used according tothe invention is not critical. Preferably, however, it is 5 to 70% byweight, in particular 10 to 60% by weight, with respect to thedispersion.

A further preferred embodiment of the invention is that wherein thedispersions contain dispersion copolymers in which the macromoleculescontain monomer units, calculated in % by weight, with respect to thecopolymer, from the following monomer groups:

a) 80 to 99.9% by weight, preferably 90 to 99% by weight, ofethylenically unsaturated hydrophobic monomers, preferably from thegroup comprising vinyl esters, methacrylic esters, acrylic esters andvinyl-aromatic compounds,

b) 0.001 to 5% by weight, preferably 0.02 to 1% by weight, of BCM saltsof the formula I, in which A.sup.⊖ has the abovementioned meaning,

c) 0 to 10% by weight, preferably 0.5 to 5% by weight, of ethylenicallyunsaturated cationic water-soluble monomers, which contain, as cationicgroups, quaternized alkylammonium, alkylsulfonium or alkylphosphoniumgroups, preferably alkylammonium groups, the alkyl radicals of which ineach case have 1 to 24 carbon atoms, it being possible for individualalkyl radicals or several alkyl radicals, preferably individual alkylradicals, to be replaced by (C₅ -C)-cycloalkyl, (C₇ -C₁₂)-aralkyl or (C₁-C₁₈)-alkyl radicals, preferably benzyl, methyl, ethyl or --CH₂ CONH₂,and

d) 0 to 19% by weight, preferably 0.1 to 6% by weight, of ethylenicallyunsaturated hydrophilic monomers containing one or more functionalgroups from the series comprising --OH, --COOH, --SO₃ H, --PO(OH) and--CONR¹ R², in which R¹ and R², which can be identical or different, areH or --CH₂ OR, where R=H or (C₁ -C₈)-alkyl, and

the dispersions also contain 0.1 to 20% by weight, preferably 0.1 to 7%by weight, of surface-active compounds from the group comprisinganionic, nonionic, cationic or amphoteric emulsifiers and also,optionally, in addition between 0 and 5% by weight, preferably 0.1 to 2%by weight, of protective colloids, in each case with respect to thetotal amount of monomer.

The preparation of aqueous anionic, cationic or amphoteric plasticdispersions according to the invention can be effected by conventionalemulsion polymerization or copolymerization, for example by the feed orpreemulsion process at 20° to 100° C., preferably at 50° to 90° C. Inthis process, in the conventional manner, a portion of the monomers ispreferably prepolymerized in the aqueous liquor and the residual amountmetered in continuously, maintaining the polymerization reaction. Inorder to obtain a particularly high content of BCM cations on thesurface of the dispersion polymer or copolymer particles it is possible,preferably in the case of copolymerizations, to meter in, for example,the monomeric BCM salts of the formula I in non-uniform amounts duringthe course of the polymerization, particularly advantageously inrelatively large amounts together with other comonomers at the start ofthe polymerization. The solids content of the biocidal plasticdispersions obtainable in the case of emulsion polymerization is in therange customary for the preparation of known anionic or nonionic paintbinder dispersions.

When plastic dispersions to be used according to the invention areprepared by emulsion copolymerization, the monomer components as can beassigned to the group listed above under a), which are used arepreferably copolymerizable, ethylenically unsaturated hydrophobiccompounds, such as vinyl esters of (C₁ -C₁₈)-carboxylic acids,preferably, for example, vinyl acetate, vinyl propionate, vinylversatate, vinyl laurate or vinyl stearate; (meth)acrylic esters of (C₁-C₈)-alcohols, preferably, for example, methyl methacrylate, butylmethacrylate, octyl methacrylate, ethyl acrylate, isobutyl acrylate and2-ethylhexyl acrylate; vinyl-aromatic compounds, preferably, forexample, styrene or vinyltoluene; vinyl chloride, ethylene,acrylonitrile, diesters of maleic acid and/or fumaric acid orvinylpyrrolidone. The monomers can be used either on their own or as amixture. Preferably, those monomers are used which lead to stabledispersion polymers and copolymers resistant to saponification. Thechoice of monomers and their mixing ratios usually depends on thedesired application properties of the dispersion, it being possible toapply the customary selection criteria known to those skilled in the artfor their formulations.

In particular, the minimum film-forming temperature (MFT) of the plasticdispersions should be below the range, or at most within the range, ofthe intended use temperatures, i.e. preferably between 0° and 80° C. andin particular between 0° and 40° C. If polymers of harder formulationare used, film-forming auxiliaries or external plasticizers can be usedin order to achieve the requisite MFT, in which case the effect thereofon the biocidal properties of the dispersions should be checkedbeforehand. If such additives are not desired, the MFT of the cationicdispersions should preferably be in the range from 0° to 25° C. Thefollowing comonomer combinations are suitable in combination withmonomeric BCM salts of the formula I and cationic monomers, veryparticularly, for example, in the weight ratios indicated below(pwt=parts by weight), for the preparation of aqueous biocidal cationicdispersions according to the invention:

    ______________________________________                                        Butyl acrylate/methyl methacrylate                                                                 10-90 pwt/90-10 pwt                                      Butyl acrylate/styrene                                                                             10-90 pwt/90-10 pwt                                      Octyl acrylate/methyl methacrylate                                                                  5-80 pwt/95-20 pwt                                      Octyl acrylate/styrene                                                                              5-80 pwt/95-20 pwt                                      Vinyl acetate/butyl acrylate                                                                       40-80 pwt/60-20 pwt                                      Vinyl acetate/vinyl versatate                                                                      50-80 pwt/50-20 pwt                                      ______________________________________                                    

However, the contents of monomer units of BCM salts of the formula I aredecisive for the biocidal properties, according to the invention, of thedispersions.

In the case where an improvement and optimization of the algicidalproperties of the biocidal dispersions are desired at the same time, itis no less important to use water-soluble cationic ethylenicallyunsaturated and copolymerizable monomers containing quaternaryalkylsulfonium, alkylphosphonium or, in particular, alkylammoniumgroups, it being possible for the alkyl radicals in each case to have1-24 carbon atoms or also to be combined to form a ring structure, butin particular can be a (C₅ -C₇)-cycloalkyl, (C₇ -C₁₂)-aralkyl or (C₁-C₁₈)-alkyl radical, methyl, ethyl, benzyl or H₂ N--CO--CH₂ radicalsbeing preferred. The concentration of these monomers should be 0.1 to10% by weight, preferably 0.5 to 5% by weight, with respect to the totalamount of all monomers.

Preferred quaternized cationic monomers are, for example,

trimethylammonioethyl acrylate chloride,

trimethylammonioethyl methacrylate chloride,

β-acetamido-diethylaminoethyl acrylate chloride,

β-acetamido-diethylaminoethyl methacrylate chloride,

acrylamidopropyltrimethylammonium chloride,

methacrylamidopropyltrimethylammonium chloride,

acrylamidoethyltrimethylammonium chloride,

methacrylamidoethyltrimethylammonium chloride,

trimethylammonioneopentyl acrylate chloride,

trimethylammonioneopentyl methacrylate chloride,

diallyl-dimethylammonium chloride and

diallyl-butylmethyl-ammonium chloride.

With respect to the spectrum of properties of the polymer dispersions tobe used according to the invention it can be advantageous in some casesto use yet further comonomers in the emulsion copolymerization,specifically ethylenically unsaturated compounds containing functionalgroups such as --OH, --COOH, --SO₃ H, --PO(OH), --NR¹ R² or --CONR¹ R²,where R¹ and R² can be identical or different and are H or --CH₂ OR,where R=H or (C₁ -C₈)-alkyl.

Preferred compounds from this group are, for example, hydroxyethylmethacrylate, hydroxypropyl methacrylate, polyhydroxypropylmethacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate,polyhydroxypropyl acrylate, methacrylic acid, acrylic acid, crotonicacid, maleic acid, fumaric acid, itaconic acid and also the half-estersof the latter three compounds, acrylamidomethanesulfonic acid,dimethylaminoneopentyl methacrylate, dimethylaminopropylmethacrylamide,dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate,2-N-morpholinoethyl methacrylate, t-butylaminoethyl methacrylate,methacrylamide, acrylamide, N-methylolmethacrylamide,N-methylolacrylamide, vinylsulfonic acid and salts thereof,acrylamidomethylpropanesulfonic acid and vinylphosphonic acid.

When using ethylenically unsaturated copolymerizable carboxylic acids,the proportion thereof should preferably be less than 10% by weight, inparticular between 0.1 and 6% by weight, with respect to the totalamount of all monomers.

To adjust the particle size of the dispersions to the desired fineness(average particle diameter 0.02 to 1.0 μm, preferably 0.05 to 0.5 μm, inparticular 0.08 to 0.15 μm), anionic or cationic and/or nonionic and/oramphoteric surface-active emulsifiers are used in the emulsionpolymerization in the customary manner, in an amount of 0.1 to 20% byweight, preferably 0.12 to 7% by weight and in particular 1 to 5% byweight, with respect to the total amount of monomers. It has been foundthat the optimum amounts of these emulsifiers required according to theinvention in the dispersions surprisingly do not adversely affect thewaterproof properties of basecoats and impregnations.

The emulsifiers used are preferably conventional nonionic surfactants,for example from the group comprising the reaction products of epoxides,such as, for example, ethylene oxide, with aliphatic, cycloaliphatic,araliphatic, aliphatic-aromatic or aromatic carboxylic acids, alcohols,phenols or amines, and also block copolymers composed of differentepoxides, such as, for example, ethylene oxide and propylene oxide.

In addition, conventional anionic surfactants, preferably, for example,surface-active ammonium salts and alkali metal salts of fatty acids(soaps), fatty alcohol sulfates, isethionic acid ethers of fattyalcohols, alkanesulfonates, alkyl benzenesulfonates, (oxethylated)sulfosuccinic acid esters, polyoxethylated fatty alcohol sulfates,alkylphenol polyoxethylate sulfates or (alkyl)naphthol polyoxethylatesulfates and fatty alcohol phosphates can be used.

Further preferred emulsifiers are, for example, primary, secondary andtertiary fatty amines in combination with organic or inorganic acids andalso, in addition, surface-active quaternary alkylammonium compounds. Inaddition, in some cases, amphoteric surfactants of zwitterionicstructure, for example of the betaine type, can also be advantageous.The said emulsifiers can be used either on their own or in combinationwith the same type or a different type in the conventional manner,provided they do not adversely affect one another because of oppositecharges or impair the stability of the dispersion.

Known protective colloids, specifically preferably those based on highmolecular weight organic compounds, which are water-soluble orwater-dispersible, develop essentially no or no pronounced interfacialactivity and have a pronounced dispersing power can also be co-used inthe preparation of the cationic dispersions. Preferred protectivecolloids are, for example, cellulose ethers, polyvinyl alcohols,polysaccharides and polyvinylpyrrolidones, it being possible for theseto contain acid/anionic or basic or cationically functional groups. Theselection depends on the particular type of dispersion and must not leadto disturbance of the coulomb repulsion of the latex particles, i.e.protective colloids having opposite charges can in general not be usedat the same time.

The amounts of protective colloid to be used depend on the desireddispersion properties, in particular the fineness of the dispersionparticles. Preferably protective colloid amounts of between 0 and 5% byweight, in particular between 0.1 and 2% by weight, with respect to thetotal amount of monomers, are optionally used in the emulsionpolymerization.

All of the preferably water-soluble and radical chain-initiating systemscustomary in emulsion polymerization can be used to initiate thepolymerization or copolymerization. Preferred initiators in the case ofthe anionic types are, for example, persulfates, such as ammoniumpersulfate, sodium persulfate and potassium persulfate; in the case ofthe purely cationically charged dispersion types, on the other hand, thecompounds used are, rather, those such as 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis-(N,N'-dimethyleneisobutyramidine)dihydrochloride, 4,4'-azobis-(4-cyanovaleric acid), H₂ O₂ or t-butylhydroperoxide.

The following, for example, are also generally usable: redox systems,such as H₂ O₂ and ascorbic acid, peroxides and polyvalent metal salts,t-butyl hydroperoxide and Rongalite, it being possible for redox systemsto be advantageous, in particular, for lowering the residual monomercontent in the post-reaction stage of the polymerization, and alsoenergy-rich radiation as well as conventional photoinitiators.

In order to control the molecular weight during the emulsionpolymerization it is also possible to use conventional regulators, suchas, for example, mercaptans or halogenated hydrocarbons in order tolower the molecular weight or, alternatively, optionally up to 5% byweight, with respect to the total amount of monomers, ofpolyethylenically unsaturated or multifunctional compounds capable ofcrosslinking, such as, for example, divinylbenzene, ethylene glycoldimethacrylate, ethylene glycol diacrylate, butanediol dimethacrylate,butanediol diacrylate, triallyl cyanurate, melamine or isocyanatoethylmethacrylate, in order to increase the molecular weight.

For the use, according to the invention, of aqueous or finely dividedplastic dispersions as priming and impregnating agents, the solidscontent thereof can preferably be adjusted to values of 3 to 40% byweight, in particular 5 to 20% by weight. In these preferred solidsconcentration ranges, the dispersions have a low viscosity and a highpenetrating power into absorbent substrates; in addition, the cationicdispersions according to the invention surprisingly also have theadvantage of generating virtually no troublesome foam and can thereforebe processed particularly advantageously.

The invention is illustrated in more detail by the following examples.

EXAMPLE 1

206.9 g of desalinated water (D water) and 1.9 g of sodium laurylpolyglycol ether sulfate (emulsifier) are initially introduced into a 2l three-necked round-bottomed flask provided with a stirrer, a droppingfunnel and a reflux condenser. An emulsion is prepared from 182.1 g ofmethyl methacrylate, 183.1 g of butyl acrylate, 11.25 g of acrylic acid,which additionally contain 1.1 g of benzimidazolylcarbamic acid methylester (BCM) in solution, with salt formation, 0.95 g of ammoniumpersulfate (APS), 3.75 g of sodium lauryl polyglycol ether sulfate and243.75 g of D water, and 15 g of this emulsion are added to the aqueousemulsifier solution initially introduced. The vessel is heated, withstirring, to 80° C., 0.175 g of APS already being added at 55° to 60° C.in order to start the polymerization. The residual monomer emulsion ismetered into the vessel in the course of 3.5 hours, with stirring, at80° C. After a post-reaction stage of 2.5 hours, the reaction mixture iscooled to room temperature (RT). 15 ml of 17% strength by weight ammoniaare added to the reaction mixture one hour after all of the monomeremulsion has been metered in and after cooling to RT has taken place. Afurther 17% by weight ammonia is added in an amount such that theresulting dispersion has a pH value of 8.5.

An anionic dispersion is obtained which has a solids content (S content)of 44.7% by weight, with respect to the dispersion, and a minimumfilm-forming temperature (MFT) of 7° C. The BCM content of the copolymeris 0.28% by weight, with respect to the copolymer.

EXAMPLE 2

420 g of D water and also 11.8 g of sodium lauryl sulfate and 4.8 g ofoxethylated nonylphenol (emulsifier combination) are initiallyintroduced into a stirred reactor as described in Example 1.

An emulsion is prepared from 663.1 g of D water, 25.5 g of sodium laurylsulfate, 6.8 g of oxethylated nonylphenol, 236.7 g of styrene, 289.3 gof butyl acrylate, 7.1 g of acrylic acid, 13.1 g of methacrylic acid and1.45 g of BCM methacrylate, which had been prepared separatelybeforehand, and 110 g of this emulsion are added to the aqueousemulsifier solution initially introduced. The vessel is heated to 80° C.with stirring, 10 ml of an initiator solution composed of 2 g ofammonium persulfate and 40 g of D water being added thereto at 60° C.After prepolymerization for 15 minutes, the residual monomer emulsion ismetered in in the course of 3 hours and the residual initiator solutionis metered in in parallel. After heating at 80° C. for a further 2hours, the reaction mixture is cooled to RT.

A finely divided, coagulate-free anionic dispersion is obtained whichhas an S content of 34.1% by weight, a pH value of 3.4 and a MFT of 12°C. The BCM content of the copolymer is 0.24% by weight, with respect tothe copolymer.

EXAMPLE 3

Example 1 is repeated except that a mixture of 258.9 g of butylacrylate, 93.7 g of methyl methacrylate and 93.7 g of styrene is used inplace of 182.1 g of methyl methacrylate and 183.1 g of butyl acrylate,and the 11.25 g of acrylic acid and the 1.1 g of BCM are replaced by amixture of 5.3 g of BCM-AMPS salt (BCMacrylamidomethylpropanesulfonate), 2.5 g of acrylic acid and 5.1 g ofmethacrylic acid. After the end of the polymerization and cooling thereaction mixture to RT, a fine to medium disperse, coagulate-freeanionic dispersion is obtained which has a solids content of 49.8% byweight, a pH value of 4.1 and a MFT of 11° C. The BCM content of thecopolymer is 0.56% by weight, with respect to the copolymer.

EXAMPLE 4

1117.5 g of D water, 4.5 g of oxethylated tridecyl alcohol, 4.5 g ofdimethyldidecylammonium chloride, 9 g of stearyldimethylbenzylammoniumchloride and 18 g of a 50% strength by weight aqueousmethacrylamidopropyltrimethylammonium chloride solution are initiallyintroduced into a stirred reactor as described in Example 1. Afteradding 45 g of a monomer mixture composed of 229.5 g of butyl acrylate,220.5 g of methyl methacrylate, 3.25 g of BCM methacrylate, 1.5 g ofmethacrylic acid, 2.23 g of BCM acrylate and 0.76 g of acrylic acid, thevessel is heated to 80° C., 0.9 g of 4,4'-azobiscyanovaleric acid (AVA)are added and the mixture is prepolymerized for 15 minutes. A further0.9 g of AVA is then added and the residual monomer mixture is addeddropwise in the course of 2 hours at 80° C., with stirring. After afurther addition of 0.45 g of AVA, the mixture is heated for a furtherone hour at 80° C. and cooled to RT. The resulting finely dividedamphoteric dispersion has an S content of 30.3% by weight, a pH value of2.6 and a MFT of 6° C. and is coagulate-free. The BCM content of thecopolymer is 0.21% by weight, with respect to the copolymer.

EXAMPLE 5

1186.2 g of D water, 19.5 g of 50% strength by weight aqueousmethacrylamidopropyltrimethylammonium chloride solution, 19.5 g oflaurylpyridinium chloride and 48 g of a monomer mixture composed of258.4 g of butyl acrylate, 229.1 g of methyl methacrylate, 9.8 g ofhydroxyethyl methacrylate and 7.3 g of BCM-AMPS salt (see Example 3) areinitially introduced into a stirred reactor as described in Example 1and heated to 80° C. After adding 1.95 g of AVA and prepolymerizing for15 minutes, the residual monomer mixture is metered in in the course of2 hours. A further 0.48 g of AVA, which has been dissolved in 10 g of Dwater at pH 7 with co-use of aqueous NaOH, is then added and thereaction mixture is stirred for 30 minutes at 80° C. After cooling toRT, a finely divided cationic dispersion is obtained which is free fromcoagulate and has an S content of 30% by weight, a pH value of 3.5 and aMFT of <0° C. The BCM content of the copolymer is 0.65% by weight, withrespect to the copolymer.

COMPARISON EXAMPLE 1

Example 1 is repeated except that the 1.1 g of BCM are omitted. A finelydivided anionic dispersion is obtained which has a solids content of44.8% by weight and a MFT of 7° C.

COMPARISON EXAMPLE 2

Example 2 is repeated except that the 1.45 g of BCM methacrylate areomitted. After cooling, the pH of the dispersion is adjusted to 8 to 8.5using about 20 ml of 17% strength by weight aqueous NH₃. The finelydivided anionic dispersion has a solids content of 34% by weight and aMFT of 11° C.

APPLICATION TESTS

The biocidal activity of the dispersions according to the invention canbe assessed by painting testpieces composed of wood (board test) orcomposed of filter paper (algae filter test) with, in each case, one ofthe dispersions, according to the invention, of Examples 1 to 5 and, forcomparison with dispersions of Comparison Examples 1 and 2, which arenot according to the invention and contain comparable amounts of solidsand placing them either on a microbially infected agar-agar nutrientmedium or in a green algae culture and observing the biocidal activityagainst fungi and algae. In detail, the procedure used can be asdescribed below.

BOARD TEST

The board test is used to test whether a wood coating offers adequateprotection against fungal growth. To this end, pine sap wood boardshaving dimensions of 50×25×5 mm (fiber direction 50 mm) are eithercoated on one side or treated in accordance with another given form ofapplication for wood protection agents (for example brief dipping) withthe biocidal dispersion or solution to be tested. After drying in airfor four weeks at RT, the coated or dip-treated board testpieces areplaced, after sterilization by UV light, with a treated testpiecesurface on infected and pre-incubated nutrient media which had beeninoculated with molds (Aspergillus niger) or blue fungi (Sclerophomapityophila and Aureobasidium pullulans) or soft rot fungi (Chaetomiumglobosom).

The board testpieces inoculated with fungi via the preincubated nutrientmedia are stored in an incubator at 29° C. and 70% relative atmospherichumidity for 4 weeks and the fungal growth on the testpiece is thenassessed in accordance with the following rating scale 0 to 4.

    ______________________________________                                        OH > 3 = no growth on the wood and inhibitory zone more                                than 3 mm wide on the agar nutrient medium                                    adjacent to the testpiece                                            OH < 3 = no growth on the wood and inhibitory zone less                                than 3 mm wide on the agar nutrient medium next                               to the testpiece                                                     0 =      no growth on the wood, no inhibitory zone next                                to the testpiece on the agar nutrient medium                         1 =      slight growth on the wood, covering less than                                 10%                                                                  2 =      growth on the wood, covering less than 30%                           3 =      distinct growth on the wood, covering 30 to                                   60%, wood attacked                                                   4 =      severe growth on the wood, covering more than                                 60%, entire wood attacked.                                           ______________________________________                                    

In order to assess the waterproof properties or the leachability of thebiocidal active compound, in a further test the primed or painted ordip-treated and dried testpieces described above are watered, in eachcase for 48 hours, 96 hours and 1 month, in running water, then driedagain, rendered germ-free by means of UV light and placed in Petridishes on the prepared and in each case specifically infected agar-agarnutrient media. Incubation and subsequent assessment of the samples inthe Petri dishes are carried out in a manner analogous to that describedabove for the unwatered samples.

ALGAE FILTER TEST

The protection against attack by algae is tested. To this end, paintedcoatings are infected with algae and placed under standardized growthconditions. In the case of a good algicidal action, the algae must notgrow on the paint coating.

In order to test the leachability of the algicide, the paint coatingsare watered for two days, four days and 1 month prior to infection withalgae. The effectiveness should not be substantially reduced as aresult.

TEST PROCEDURE

Round paper filters having a diameter of 5.5 cm are painted on one orboth sides with the dispersion to be tested and dried at roomtemperature for 2 to 3 days. The weight of the dry film is determined byweighing before and after painting. After drying, individual filters areplaced in running water, in each case for 48 or 96 hours or 1 month, andthen dried again.

Prior to infection with algae, the dry filters are sterilized on bothsides under UV light and placed individually in sterile glass Petridishes of 9 cm φ. The infection with 10 ml of green algae culture(strain used: Chlorella pyrenoidosa), which has been cultured in a Knopnutrient solution and is 8 to 21 days old, then follows. The test iscarried out at 16° to 20° C. in a chamber with diffuse light. In orderto promote more rapid growth of the green algae, light is provided atnight. After 14 days, the paint coatings are assessed in accordance withthe following rating scale 0 to III:

    ______________________________________                                        0 =          no growth on the paint coating                                   I =          slight growth on the paint coating                               II =         distinct growth on the paint coating                             III =        severe growth on the paint coating.                              ______________________________________                                    

The results are summarized in Table 2. They show the outstandinginhibitory action of biocidal paint coatings, according to theinvention, from Examples 1 to 5, both in the fungus inhibition test andin the algae inhibition test, and in each case also after prior wateringof the paint coating for up to 1 month, compared with paint coatings ofthe BCM-free plastic dispersions of Comparison Examples 1 and 2, whichare not according to the invention, and the commercially availablebiocidal wood protection scumble Sadolin classic from Sadolin GmbH. Inthis context it is particularly noteworthy that the samples preservedaccording to the invention show virtually no loss of theirfungus-inhibiting action as a result of watering, the amphotericdispersion of Example 4 and the cationic dispersion of Example 5 are, inaddition, characterized by an exceptionally strong algicidal action andthe samples according to the invention, compared with samples which havebeen painted with conventional dispersions according to ComparisonExamples 1 and 2 or with Sadolin classic, also display unexpectedly goodinhibitory properties overall per se, as already mentioned.

                                      TABLE 2                                     __________________________________________________________________________    Test to determine the biological inhibitory action of paint coatings          composed of                                                                   biocidal plastic dispensions on wood testpieces and                           filter paper [W = wood testpiece; F = filter paper testpiece;                 w.w. = test without prior watering of the testpiece; h-w = prior              testpiece watering period in hours, or m-w in months; fungus test period      = 4 weeks,                                                                    rating scale 0 (no attack by fungi) to 4 (severe attack by fungi).            Algae test period = 14 days, rating scale 0 (no growth of algae) to III       (severe growth of algae)]                                                     __________________________________________________________________________    Testpiece                                                                     paint                                                                         coating                                                                       composed                                                                      of plastic                                                                             Biological test organisms and test result rating figures             dispension                                                                             Blue fungi          Molds                                            from     w.w. 48 h-w.                                                                            96 h-w.                                                                            1 m-w.                                                                             w.w. 48 h-w.                                                                            96 h-w.                                                                            1 m-w.                            __________________________________________________________________________    Example 1 (W)                                                                          CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             0    0    0    0    0                                 Example 1 (F)                                                                 Example 2 (W)                                                                          0    0    0    0    0    1    1    2                                 Example 2 (F)                                                                 Example 3 (W)                                                                          CH > 3                                                                             CH > CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             0    CH > 3                                                                             0                                 Example 3 (F)                                                                 Example 4 (W)                                                                          0    0    0    1    0    0    2    1                                 Example 4 (F)                                                                 Example 5 (W)                                                                          CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             CH > 3                                                                             CH > 3                            Example 5 (F)                                                                 Comp. Ex. 1 (W)                                                                        4    4    4    4    4    4    4    4                                 Comp. Ex. 1 (F)                                                               Comp. Ex. 2 (W)                                                                        4    4    4    4    4    4    4    4                                 Comp. Ex. 2 (F)                                                               Commercially                                                                           0    0    1    3    4    4    4    4                                 available                                                                     wood protec-                                                                  tion scumble                                                                  (Sacblin                                                                      classic)                                                                      __________________________________________________________________________    Testpiece                                                                     paint                                                                         coating                                                                       composed                                                                      of plastic     Biological test organisms and test result rating figures       dispersion     Soft rot molds      Algae                                      from           w.w. 48 h-w.                                                                            96 h-w.                                                                            1 m-w.                                                                             w.w.                                                                             48 h-w.                                                                           96 h-w.                                                                           w.w.                            __________________________________________________________________________    Example 1 (W)  CH > 3                                                                             CH> 3                                                                              CH > 3                                                                             CH > 3                                          Example 1 (F)                      0  0   I   II                              Example 2 (W)  0    0    1    2                                               Example 2 (F)                      0  I   II  III                             Example 3 (W)  0    0    0    0                                               Example 3 (F)                      0  0   II  II                              Example 4 (W)  0    0    1    1                                               Example 4 (F)                      0  0   0   0                               Example 5 (W)  CH > 3                                                                             0    CH > 3                                                                             0                                               Example 5 (F)                      0  0   0   0                               Comp. Ex. 1 (W)                                                                              4    4    4    4                                               Comp. Ex. 1 (F)                    I  II  III III                             Comp. Ex. 2 (W)                                                                              4    4    4    4                                               Comp. Ex. 2 (F)                    I  II  II  III                             Commercially   1    3    4    4                                               available                                                                     wood protec-                                                                  tion scumble                                                                  (Sacblin                                                                      classic)                                                                      __________________________________________________________________________

We claim:
 1. A biocidal monomeric BCM salt of the formula I ##STR7## inwhich A.sup.⊖ is an ethylenically unsaturated anion selected from thegroup consisting of acrylate, methacrylate, crotonate, itaconate,styrenesulfonate, acrylamidomethyl-propanesulfonate, acrylamidoglycolicacid methyl ether, and acrylamidomethyl-phosphonate.